KDD Papers

Revisiting power-law distributions in spectra of real world networks

Nicole Eikmeier (Purdue University);David Gleich (Purdue University)


By studying a large number of real world graphs, we find empirical evidence that most real world graphs have a statistically significant power-law distribution with a cutoff in the singular values of the adjacency matrix and eigenvalues of the Laplacian matrix in addition to the commonly conjectured power-law in the degrees. Among these results, power-laws in the singular values appear more consistently than in the degree distribution. The exponents of the power-law distributions are much larger than previously observed. We find a surprising direct relationship between the power-law in the degree distribution and the power-law in the eigenvalues of the Laplacian that was theorized in simple models but is extremely accurate in practice. We investigate these findings in large networks by studying the cutoff value itself, which shows a scaling law for the number of elements involved in these power-laws. Using the scaling law enables us to compute only a subset of eigenvalues of large networks, up to tens of millions of vertices and billions of edges, where we find that those too show evidence of statistically significant power-laws.